Term
When do we use an independent measures ANOVA? 

Definition
when there is more than 2 groups or levels of the IV 


Term
What's the difference between independent measures, repeated measures, and mixed ANOVA designs? 

Definition
independent: repeated: mixed: more than 1 IV at the same time 


Term
What is generally learned from ANOVA? 

Definition
Tells whether means of samples that undergo different levels of the IV come from populations with the same or different means. 


Term
What are the hypotheses for ANOVAs? 

Definition
H0: μ1 = μ2 = μ3 = …μk H1: At least one μ is different from others. 


Term
Why do we need ANOVA when a series of t tests would test several hypotheses? 

Definition
The overall chance of type 1 error is the sum of all individual scores > if you conduct 5 HT at alpha .05, the end chance of type 1 error is .25. It is also a lot more work. 


Term
What is the difference between testwise and experimentwise alpha level? 

Definition
testwise: level of error set for 1 test experimentwise: level of all tests combined on 1 set of data or study
*every test conducted increases 2nd type of alpha level 


Term
How does ANOVA help with the experimentwise alpha level? 

Definition
makes all comparisons between means simultaneous and keeps alpha at level set by experimentor (even if compare many levels or groups) 


Term

Definition
is the variable manipulated – Called a factor in ANOVA designs – May have many factors in experiment 


Term
QuasiIndependent Variable 

Definition
not actively manipulated, but may affect experiment (ie gender, age, education, etc) 


Term

Definition
Variable that designates the groups being compared 


Term
BetweenTreatments Variance 

Definition
calculate the variance between treatment groups to provie a measure of the overall differences between treatment conditions > really measures the differences between sample means 


Term
WithinTreatments Variance 

Definition
The variability within each sample > provides a measure of the variability inside each treatment condition 


Term
Why is variance partitioned in ANOVA? 

Definition
In this way ANOVA shows if differences between sample means are greater than would be expected by chance. 


Term

Definition
The MS value in the denominator of the Fratio is called the error term. This MS value is intended to measure the amount of error variability  variability in the data for which there is no systematic or predictable explanation. It is used as a standard for determining whether or not the differences between treatments (measured by MSbtwn) are greater than would be expected just by chance. 


Term

Definition
MSbetween  simply measure how much difference exists between the treatement means. The bigger the mean differences, the bigger the Fratio. 


Term

Definition
MSwithin  measures the variance of the scores inside each treatment; that is, the variance for each of the separate samples. In general, the larger the sample variances, the smaller is the Fratio. 


Term
What contributes to the between groups source of variance in the independent measures ANOVA? 

Definition
MSbetween is composed of (SSbetween) / (dfbetween) 


Term
What contributes to teh within group source of variance in this test? 

Definition
MS within = (SSwithin) / (dfwithin) 


Term

Definition
the number of individual treatment conditions; the number of levels of treatments 


Term

Definition
the number of raw scores in each individual treatment condition 


Term

Definition
total number of raw scores in the entire study; OR k times n, when n is constant 


Term

Definition
sum of all scores in the entire study (sigma X) 


Term

Definition
grand total, sum of all scores in the entire study (sigma T) 


Term

Definition


Term

Definition
 family of curves based on 2 separate dfs  tells all values F could be and probability of getting each  all F values are positive because they are variances  positively skewed (always 1tailed)  median value is about 1; the more extreme the Fobt, the more likely you can reject Ho  Fobt = 1.00 > retain null 


Term
Why do we need 2 dfs to look up a critical F value? 

Definition
df between (numerator) > top df within (denominator) > down side 


Term
What assumptions are required for IM ANOVA? 

Definition
 scores are drawn from normal distributions (large enough sample size)  homogeneity of variance (errors are unrelated)  observations are independent  violations of assumptions dealt with in separate tests after F test is run
* the only way groups can differ is in their means 


Term
How is sample variance accounted for in ANOVA? 

Definition
– MSwithin works like s^2p 


Term

Definition
– When using 2 groups / treatmen conditions – ANOVA may be used with 2 groups, under certain conditions 


Term

Definition
 Percentage of variance accounted for due to treatment  Tells how much of variability between scores explained by treatment effect
η = SSb / SSt 


Term

Definition
Determine which μ or μs actually different from others – Pairwise comparisons compare just 2 μs –May be planned or unplanned –Must keep experimentwise alpha in mind to avoid Type I error so don’t run too many…  designed to reduce type 1 error 


Term
Give 2 examples of post hoc tests 

Definition
1. Dunn test: divide alpha by number of planned comparisons – Plan 2 post hoc comparisons – 0.05/2 = 0.025 is new alpha for each post hoc test
2. Tukey’s HSD: Single value determines minimum difference between treatments necessary for significance  better for unplanned comparisons HSD = q (sq.rt. MSw/n) 

